Envelope with adhesive closure for open mailing



Jan. 13, 1970 w. KNITTEL 3,489,33

ENVELOPE WITH ADHESIVE CLOSURE FOR OPEN MAILING Filed Nov. 15, 1 6' 2 Sheets-Sheet 1 INVENTOR 415?? N Km TTEL.

3 "Jar-ls 4: 60

/ *mawreys Jan. 13, 1970 w. KNITTEL 3, 39,

ENVELOPE WITH ADHESIVE CLOSURE FOR OPEN MAILING Filed Nov. 15, 196? 2 Sheets-Sheet 2 5/? F28 k/v/rrEII U y INVENTOR United States Patent Cl. 229--80 1 Claim ABSTRACT OF THE DISCLOSURE An envelope for open mailing has the usual open gummed sealing flap and a closed adhesive seal the glutinative strip of which is unilaterally applied to a part of the envelope and covered by the respective part of the envelope to which no glue is applied.

The present invention relates to an envelope for Open mail which has an adhesive flap. The adhesive flap most widely used for the purpose of post ofiice checking of printed matter, etc., is formed by two coinciding glutinative strips, one of which is applied to the rear surface of the envelope and the other on the inside of the opened flap. These two glued strips usually consist of latex and when the envelope is closed the two latex halves adhere together. Because of the adhesive strength of the gummings the envelope may be opened and closed as many times as desired. However, as the two respective gummings are not air-protected the envelopes cannot be stored for a long time because of the danger of intrusion of dust and dirt and of drying up of the gumming substance.

Printed matter and similar open mail form a large part of the overall mail and are often mailed in large quantities at a time. In the sourse of rationalisation automatic machines are used to slip the material to be mailed into the envelope at its open broadside. The conventional adhesive flap with its two gummed sides is not particularly suitable for this process. Therefore, when envelopes are machine filled they are often provided with the usual wet gummings at the side at which the material to be mailed is slipped in and are properly sealed at this side, while an apparent closure allowing checking by the postal authority is provided at another side, mostly a narrow side, of the envelope. This apparent closure usually consists of an elongated folded flap which is not closed and forms a relatively large opening to which other pieces of mail may easily attach themselves or which may allow the contents of the envelope to get lost in transit. Also, it raises the production cost of the envelope because of the increased paper requirement.

It is the object of the invention to provide envelopes for open mailing with adhesive sealing fiaps in such a manner that they can be stored indefinitely, require a minimum of material and may be machine filled and closed without any difficulty. The adhesive closure according to the invention of an envelope which is also provided with an open gummed fiap for proper sealing consists of a strip of adhesive which is unilaterally applied to a part of the envelope and is covered by a part of the envelope which is not glued. This provides for the required apparent closure. The unilaterally applied strip of adhesive preferably consists of a synthetic resin glue, the adhesion force of which being greater than its cohesion. Therefore a small portion of said glue is as a thin coating transferred to the side of the envelope which has not been glued. This coating cooperates with the strip of adhesive and permits repeated opening and closing of the adhesive closure thus obtained. The adhesive closure only serves for the checking by the postal authorities,

3,489,332 Patented Jan. 13, 1970 ice while the opening through which the material to be mailed is slipped into the envelope is sealed by the conventionally gummed flap. The envelope for open mailing may be machine filled and sealed in the same manner as an ordinary envelope for closed mailing, as its gumming at the flap is of the conventional type. In the adhesive closure according to the invention the unilaterally applied synthetic resin glue, because of it being covered by the corresponding part of the envelope, retains its adhesive power even after long time of storage as the synthetic resin glue is protected from the surrounding air by the covering and therefore cannot dry up or become dusty or dirty.

Where the letters are filled by machine, the part of the envelope which does not carry the glue is pressed on the unilaterally applied strip of synthetic resin glue under even pressure so that the same intensity of adhesion over the whole glued surface is ensured. The envelopes which are provided with the adhesive closure may be continually manufactured from sheets or in the rotary method. The adhesive closure may be provided at a broad or narrow side of the envelope. It is practical to provide the synthetic resin glue at the inside of the flap of the adhesive apparent closure. However, there is no disadvantage in applying it to the corresponding surface of the envelope.

The invention is further disclosed inthe following specification and accompanying drawing, which is part of this specification. In the drawing,

FIG. 1 is a view of an envelope ready to be filled with the material to be mailed in which the adhesive apparent closure is closed;

FIG. 2 is a view of the envelope of FIG. 1 in which the adhesive apparent closure is open;

FIG. 3 is a view of another embodiment of the invention.

The envelope, which consists of paper or cardboard, is at one broad side provided with an open flap 1 to the inside of which a strip of gumming 2 is applied. After the envelope is filled flap 1 is in the usual manner turned over and pressed on the rear surface 3 of the envelope, thus firmly sealing it at this side. The left narrow side of the envelope is permanently closed by a rigidly glued edge 4. The opposite narrow side is according to the invention provided with an adhesive apparent closure the closing flap 5 of which has at its inside surface a strip 6 of synthetic resin glue. After turning over flap 5 the strip 6 transfers to the rear surface 3 of the envelope a glue coating 7 and, due to the adhesive power of the two glued surfaces, enables repeated opening and closing of flap 5.

The envelope for open mailing shown in FIG. 1, which is ready for use, has the same shape as a normal envelope for closed mailing because the closing flap 5 of the adhesive apparent closure is closed from the beginning and is not used for slipping in the material to be sent. The envelope is only filled on the side of flap 1. The envelope according to the invention may therefore be filled and sealed by machine in the same manner as a normal envelope. The flap 5 alreadys adheres to the rear surface 3 of the envelope when the material to be sent is slipped in because the coating 7 was transferred from the glue strip 6 to rear surface 3 of the envelope as the envelope was manufactured. It is therefore ready to be repeatedly opened and closed by the postal authorities, and neither can other pieces of mail be caught in the envelope nor can the contents of the envelope fall out.

In the embodiment of FIG. 3 the envelope has a conventional triangular flap 11 the inside of which is provided with a gumming 12. The area of the tip 13 of flap 11 is not gummed. The opposite flap 14 of the envelope has at its inside the unilaterally applied strip 15 of synthetic resin glue, which is interrupted at the center so that an area 16 free, from glue is caused to be underneath the ungummed area 13. When the envelope is manufactured the flap 14 with its inside strip 15 of synthetic resin glue is by machine action pressed on the rear surface 17 of the envelope and in the same manner as in the first embodiment shown in FIGS. 1 and 2 transfers a thin coating of glue to surface 17, which coating forms an adhesive closure together with the glue strip 15 of flap 14.

The material to be sent is slipped into the envelope in the usual manner, which is through the open flap 11, whereupon flap 11 is turned over to the rear surface of the envelope and firmly affixed to it. If the postal authorities intend checking the contents for compliance with postal requirements the envelope is slightly cambered in its center portion, whereby the area 16, which is free from glue, moves out of the sphere of area 13 so that the flap 14 can easily be grasped by its tip and pulled up.

The invention is of like advantage for envelopes or wrappings of paper, carboard or other materials and with 20 their respective adhesive apparent closures may be manufactured from sheets or in a rotary process to be ready for use.

What I claim is:

1. An envelope having a front surface and a rear surface, a filling opening being provided between the two surfaces along one edge of the envelope and an inspection opening being provided between the two surfaces along another edge of the envelope, said front surface having an angular flap foldable over the rear surface to close said filling opening, said flap having a strip of gumming extending along its two sides, the filling opening being open when the fiap is not folded, another angular flap foldable over the rear surface to temporarily close said inspection opening, the tip of the first-mentioned flap being devoid of gumming and extending over the tip of the secondmentioned flap when the envelope is closed, the secondmeutioned flap having upon its inner surface a strip of synthetic resin glue extending along its two sides, the adhesive force of the glue being greater than its cohesion, the tip of the second-mentioned flap being devoid of glue, whereby the tip of the first-mentioned flap can be raised to engage and open the second-mentioned flap.

References Cited UNITED STATES PATENTS 917,369 4/1909 Skinner 229-68 1,121,922 12/1914 Halsey 229-80 3,265,289 8/1966 Hiersteiner 229-80 3,348,762 10/1967 Kasinkas 2298O 3,313,471 4/1967 Dickard et al. 229-62 25 DAVID M. BOCKENEK, Primary Examiner US. Cl. X.R. '22968 

